Lithographic apparatus, positioning system for use in a lithographic apparatus and method

Abstract

A lithographic apparatus having a reference body and a positioning system, the positioning system including a main body; a reaction body; an actuator; and a controller. The main body is moveable relative to the reference body along a path in a first direction and a second opposite direction. The reaction body is moveable relative to the main body along a further path in the first and second directions and is moveably connected to the reference body to be moveable relative to the reference body in the first and second directions. The controller provides a first and a second signal to the actuator. The actuator is arranged between the main body and the reaction body to accelerate the main body in the first direction and to accelerate the reaction body in the second direction under control of the first signal, and to accelerate the main body in the second direction and to accelerate the reaction body in the first direction under control of the second signal. The controller determines when the reaction body moves in the second direction and to provide the second signal after the first signal to the actuator when the reaction body moves in the second direction along the further path.

What is claimed is: 
     
       1. A lithographic apparatus having a reference body and a positioning system, the positioning system comprising:
 a main body; 
 a reaction body; 
 an actuator; and 
 a controller; 
 wherein the main body is moveable relative to the reference body along a path in a first direction and a second direction, wherein the first direction is opposite to the second direction, 
 wherein the reaction body is moveable relative to the main body along a further path in the first direction and the second direction, 
 wherein the reaction body is moveably connected to the reference body so as to be moveable relative to the reference body in the first direction and the second direction, 
 wherein the controller is arranged to provide a first signal and a second signal to the actuator, 
 wherein the actuator is arranged between the main body and the reaction body so as to accelerate the main body in the first direction and to accelerate the reaction body in the second direction under control of the first signal, and 
 so as to accelerate the main body in the second direction and to accelerate the reaction body in the first direction under control of the second signal, 
 wherein the controller is arranged to determine when the reaction body moves in the second direction, and 
 wherein the controller is arranged to provide the second signal after the first signal to the actuator when the reaction body moves in the second direction along the further path. 
 
     
     
       2. The lithographic apparatus of  claim 1 , wherein the reference body and the reaction body connected to the reference body form a dynamic system having an eigenmode,
 wherein the eigenmode is characterized by a movement of the reaction body relative to the reference body at least partly in the first direction and the second direction, 
 wherein the eigenmode has a corresponding period, and 
 wherein the controller is arranged to provide the first signal and the second signal with a length of time between the first signal and the second signal, wherein the length of time is determined by the corresponding period. 
 
     
     
       3. The lithographic apparatus of  claim 2 , wherein the reaction body comprises a reaction mass and a flexible element, wherein the flexible element moveably connects the reaction mass to the reference body. 
     
     
       4. The lithographic apparatus of  claim 3 , wherein the flexible element is adjustable so as to select the corresponding period. 
     
     
       5. The lithographic apparatus of  claim 1 , comprising a projection system for projecting a radiation beam on a substrate, wherein the main body is a part of the projection system. 
     
     
       6. The lithographic apparatus of  claim 1 , wherein the positioning system comprises a sensor for providing a sensor signal to the controller, the sensor signal being indicative of when the reaction body is moving in the second direction along the further path. 
     
     
       7. A positioning system for use in a lithographic apparatus having a reference body, the positioning system comprising:
 a main body; 
 a reaction body; 
 an actuator; and 
 a controller; 
 wherein the main body is moveable relative to the reference body along a path in a first direction and a second direction, wherein the first direction is opposite to the second direction, 
 wherein the reaction body is moveable relative to the main body along a further path in the first direction and the second direction, 
 wherein the reaction body is moveably connectable to the reference body so as to be moveable relative to the reference body in the first direction and the second direction, 
 wherein the controller is arranged to provide a first signal and a second signal to the actuator, 
 wherein the actuator is arranged between the main body and the reaction body so as to accelerate the main body in the first direction and to accelerate the reaction body in the second direction under control of the first signal, and 
 so as to accelerate the main body in the second direction and to accelerate the reaction body in the first direction under control of the second signal, 
 wherein the controller is arranged to determine when the reaction body moves in the second direction, and 
 wherein the controller is arranged to provide the second signal after the first signal to the actuator when the reaction body moves in the second direction along the further path. 
 
     
     
       8. The positioning system of  claim 7 , comprising a sensor for providing a sensor signal to the controller, the sensor signal being indicative of when the reaction body is moving in the second direction along the further path. 
     
     
       9. A method for limiting a magnitude of an excursion of a reaction body in a lithographic apparatus, wherein the lithographic apparatus comprises a reference body, a main body and a reaction body,
 wherein the main body is moveable relative to the reference body along a path in a first direction and a second direction, wherein the first direction is opposite to the second direction, 
 wherein the reaction body is moveable relative to the main body along a further path in the first direction and the second direction, 
 wherein the reaction body is moveably connected to the reference body so as to be moveable relative to the reference body in the first and second direction, the method comprising:
 accelerating the main body in the first direction and accelerating the reaction body in the second direction under control of a first signal; 
 accelerating the main body in the second direction and the reaction body in the first direction under control of a second signal; 
 providing the second signal after providing the first signal when the reaction body moves in the second direction along the further path. 
 
 
     
     
       10. The method of  claim 9 , wherein the reference body and the reaction body connected to the reference body form a dynamic system having an eigenmode,
 wherein the eigenmode is characterized by a movement of the reaction body relative to the reference body at least partly in the first direction and the second direction, and 
 wherein the eigenmode has a corresponding period, the method comprising:
 providing the first signal and the second signal with a length of time between the first signal and the second signal, wherein the length of time is determined by the corresponding period. 
 
 
     
     
       11. The method of  claim 9 , comprising:
 providing a sensor signal, the sensor signal being indicative for when the reaction body moves in the second direction along the further path.